Investigators believe a late model Holden sedan was travelling south on Mount Baimbridge Road towards Hamilton when it appears to have lost control and rolled a number of times on a straight stretch of road, coming to rest next to a power pole just before 3am.

The two 19-year-old male occupants from Hamilton, both unlicensed and on learner permits, were thrown from the car.

One died at the scene and another was taken to Hamilton hospital with life threatening injuries before being flown to the Royal Melbourne Hospital, arriving about 9.30am.

An Ambulance Victoria spokesman said the surviving teenager was in critical condition and on life support with head and facial injuries, as well as serious leg injuries.

Mount Baimbridge Road will be closed in both directions from Beveridge’s Road to Kenny’s Road while police process the scene.

Police are still trying to determine which of the car occupants was driving at the time of the crash.

Melbourne's Major Collision Investigation Group are investigating a 500-metre stretch of road around the scene for evidence.